Paul Prescod writes:
>> Thank you for your attention to web-friendly SOAP.
Thank you for your help in understanding the issues!
>> ...[specific proposal on endpoints...see attached mail...]
I agree with the spirit of this, and with putting the necessary guidance
in the primer. I have some discomfort with the term "endpoint", which is
a formal term in WSDL but not in SOAP. I think the WSDL group should
decide how to name such abstractions in a situation where one "big"
resource (I serve weather reports) is offering many finer grained
resources ("each of the zillion reports"). Maybe each is an "endpoint"
maybe not. Note that one is likely to be a relatively static URI, in the
sense that it represens the service as a whole, while the others are
likely to be a class of relatively dynamic resources that appear as new
reports become available. It wouldn't surprise me that WSDL will want
somewhat separate constructions to model these (perhaps endpoint for one,
and something else for the other?)
In any case, SOAP is not WSDL, and I suggest we avoid the term endpoint
altogether. How about something like:
"One of the principles of Web Architecture is that all important
resources should be identified by URIs. This implies that many
well-architected SOAP services will be embodied as large
numbers or resources, each with its own URI. Indeed, many
such resources are likely to be created dynamically during
operation of the service, as new information becomes available.
For example, a service offering stock prices might use
a distinct URI for each stock tracked, and perhaps for
each date and time for which quotes are provided."
Of course, I speak for myself and not for the protocols WG.
------------------------------------------------------------------
Noah Mendelsohn Voice: 1-617-693-4036
IBM Corporation Fax: 1-617-693-8676
One Rogers Street
Cambridge, MA 02142
------------------------------------------------------------------
Paul Prescod <paul@prescod.net>
Sent by: xml-dist-app-request@w3.org
06/14/02 06:25 AM
To: "xml-dist-app@w3.org" <xml-dist-app@w3.org>
cc: (bcc: Noah Mendelsohn/Cambridge/IBM)
Subject: Web-friendly SOAP
Thank you for your attention to web-friendly SOAP.
I feel that the SOAP specifications should call particular attention to
an aspect of Web Architecture which is commonly misunderstood by web
services creators. This is especially true for the Primer which will
give programmers a flavour of SOAP usage. I propose:
"One of the principles of Web Architecture is that all important
resources should be identified by URIs. This implies that most SOAP
services will have many endpoints and that SOAP services that create and
destroy resources (e.g. purchase orders, calendars) will also create and
destroy endpoints."
It is my personal sense that giving URIs to resources is not a large
burden and will greatly improve the interoperability of web services.
Unfortunately this is quite difficult with today's SOAP toolkits. This
is understandable because the original "SOAP style" was not based upon
web architecture principles. Now that we are trying to move SOAP into
accordance with web architecture I think we need to point out areas
where the installed toolkit base is out of sync.
I would like to see future SOAP toolkits have first-class support for
mapping logical objects to URIs as HTTP toolkits do.
Paul Prescod